Overview

Last seen: November 20, 1983, at her residence in Cheyenne, Wyoming. NamUs records November 21, 1983, as her last known contact date, and some secondary sources therefore use November 21 as the date she disappeared.

What happened: Valdez-Blackburn was seen loading her yellow Dodge Ram pickup truck and was believed to be preparing to travel from Cheyenne to Denver, Colorado, to visit a friend. She never arrived, and no confirmed trace of her has publicly emerged.

Case status: This remains a missing-person investigation. Authorities have not publicly classified Karen’s disappearance as a homicide, and the Air Force has stated that available evidence does not establish whether her disappearance was voluntary or involuntary.

Detailed Case Breakdown

Karen Lee Valdez-Blackburn: The 1983 Disappearance of an Air Force Sergeant in Wyoming

Karen Lee Valdez-Blackburn vanished from Cheyenne, Wyoming, in November 1983 while serving as a vehicle mechanic with the U.S. Air Force. More than four decades later, her whereabouts remain unknown, and the Air Force Office of Special Investigations continues to seek information about what happened to her.

Brief Case Summary

Last seen: November 20, 1983, at her residence in Cheyenne, Wyoming. NamUs records November 21, 1983, as her last known contact date, and some secondary sources therefore use November 21 as the date she disappeared.

What happened: Valdez-Blackburn was seen loading her yellow Dodge Ram pickup truck and was believed to be preparing to travel from Cheyenne to Denver, Colorado, to visit a friend. She never arrived, and no confirmed trace of her has publicly emerged.

Case status: This remains a missing-person investigation. Authorities have not publicly classified Karen’s disappearance as a homicide, and the Air Force has stated that available evidence does not establish whether her disappearance was voluntary or involuntary.

Who Was Karen Lee Valdez-Blackburn?

Karen Lee Valdez-Blackburn was serving as a sergeant in the United States Air Force when she disappeared. She worked as a vehicle mechanic assigned to the 90th Transportation Squadron at F.E. Warren Air Force Base in Cheyenne. The Air Force Office of Special Investigations reported that she was approximately 25 years old at the time, while NamUs and several later databases list her as 26.

She was described as a white woman with brown hair and blue eyes, approximately 5 feet 1 to 5 feet 2 inches tall and weighing roughly 115 to 118 pounds. Investigators have also noted that she had family connections in Florida.

The Final Known Hours

According to the Air Force Office of Special Investigations, Karen was last seen on November 20, 1983, loading belongings into a yellow Dodge Ram pickup truck bearing Colorado license plate 4250JX. A friend reportedly heard her indicate that she was leaving. Investigators believe she may have intended to drive south from Cheyenne to Denver to visit a friend.

She never reached the expected destination. Later checks failed to reveal information establishing where she went or what happened after she left Cheyenne. The truck has remained an important detail in public descriptions of the case, but authorities have not publicly announced a recovery of Karen or evidence explaining her disappearance.

There is a small but important date discrepancy in public records. The Air Force’s 2024 cold-case appeal states that Karen was last seen loading her truck on November 20, while NamUs identifies November 21, 1983, as the date of last known contact. For that reason, both dates appear in established case databases.

Initially Listed as a Deserter

One month after Karen vanished, on December 21, 1983, she was officially placed in deserter status. That early classification appears to have shaped the handling of the disappearance during its first years.

Decades without verified contact ultimately changed the way authorities viewed the case. Karen is now treated as a missing person rather than simply as a service member who voluntarily abandoned her duties. The Air Force has specifically said there is not enough evidence to determine whether she disappeared willingly or whether something happened to her.

That distinction is significant. Despite the length of time Karen has been missing, investigators have not publicly announced evidence proving that she was killed. Her case therefore should not be described as a confirmed homicide.

Renewed Cold-Case Investigation

A major public development came on June 12, 2024, when the Air Force Office of Special Investigations issued a renewed appeal for information in Karen’s case. The agency’s Cold Case Team said investigators had been reviewing old evidence while looking for new information that could clarify Karen’s actions and movements before she disappeared.

Special Agent Shelley Pillman said modern technology and new tips from the public could provide opportunities that were unavailable when Karen vanished in 1983. OSI specifically encouraged anyone with information — even something that may have appeared insignificant at the time — to contact investigators.

The renewed appeal confirms that the disappearance remains of investigative interest to OSI. The agency has not publicly identified a suspect, named a person of interest, announced an arrest, or disclosed evidence establishing that Karen met with foul play.

Newer Case-Database Activity

Karen’s case was added to The Doe Network in 2024 under reference 4842DFWY, giving the disappearance another long-term missing-person database presence. The Charley Project also added a case file in August 2024.

Publicly available case aggregators continued to show Karen as missing in 2026. One database reproducing NamUs information listed the case as open and indicated that its NamUs-sourced information had been updated in June 2026. That database activity does not itself indicate a new investigative breakthrough, but it does show the case continuing to circulate in current missing-person records.

As of the latest publicly located information, no official announcement has reported that Karen has been found or that her disappearance has been solved.

Questions That Remain Unanswered

The most important unanswered question is whether Karen actually left Cheyenne for Denver as planned. Investigators have never publicly established where she went after she was seen preparing to leave, whether anyone saw her along the route, or whether she reached another location before disappearing.

The identity and knowledge of the Denver friend may also be significant, although law enforcement has not publicly disclosed enough information to draw conclusions about that person. There is likewise no publicly announced suspect or verified evidence supporting accusations against anyone connected with Karen.

The yellow Dodge Ram remains one of the clearest identifying details from her final known movements. Any historical records, photographs, recollections, vehicle sightings, correspondence or conversations connected to Karen during November 1983 could potentially help investigators reconstruct what happened.

More Than Four Decades Without Answers

Karen Lee Valdez-Blackburn’s disappearance remains one of Wyoming’s long-running missing-person cases with a direct military investigative connection. What began as an apparent absence from duty developed into a case in which authorities could no longer determine whether she left voluntarily at all.

The 2024 appeal by the Air Force Office of Special Investigations demonstrated that investigators were still actively seeking information decades after Karen vanished. Her NamUs record remains MP38394, and her case continues to be publicly listed as missing.

Anyone who remembers Karen, saw her yellow Dodge Ram, knew of her travel plans, communicated with her in November 1983, or possesses information that was never reported is encouraged to contact the Air Force Office of Special Investigations.